Material unloading device



y 1957 F. J. AVERY 2,797,831

MATERIAL UNLOADING DEVICE Filed July 6, 1954 2 Sheets-Sheet 1 I INVENTOR. /l v v ATTORNEYS.

July' 2, 1957 F. J. AVERY 2,797,831

' MATERIAL UNLOADING DEVICE Filed July 6, 1954 2 Sheets-Shec 2 ATTORNEYS.

United States Patent MATERIAL UNLOADIN G DEVICE Fred J. Avery, La Grange, IlL, assignor of one-half to Hugo L. Kuehlthau, Cook County, Ill.

Application July 6, 1954, Serial No. 441,443

11 Claims. (Cl. 214-317) This invention relates to a material unloading device and more particularly to an apparatus for use with a fork lift truck or the like to transport and unload loose material.

In handling loose material such as small parts, scrap and the like with fork lift trucks, it is highly desirable to be able to discharge the material from the bottom of a container carried by the truck. For this purpose it has been proposed to use drop bottom boxes or containers to be picked up by the forks of the truck together with mechanism to elevate the boxes above the truck forks. The boxes are provided with hinged bottoms which drop when the boxes are elevated to allow the contents to spill out.

Such mechanisms normally raise the boxes straight up so that a substantial elevation thereof is necessary before the material can be discharged. A relatively long stroke of the elevating mechanism is, therefore, required to effect complete emptying of the box.

It is one of the objects of the present invention to provide a material unloading device in which discharge of material from the container or box is started after a relatively small elevation of the container and may be completely effected with a relatively short stroke of the mechanism.

Another object is to provide a material unloading device in which the container is tilted simultaneously with elevation thereof.

Still another object is to provide a material unloading device in which one tilting means is effective during initial raising of the container to tilt the container through a limited degree of movement and additional tilting mechanism becomes efliective during continued raising of the container to tilt it an additional amount.

According to one feature of the invention the initial tilting mechanism is a cam mechanism which provides an eflicient mechanical advantage during initial movement and the additional mechanism is in the form of levers which reach an efiicient operating angle at termination of the cam throw. In the preferred construction there are two sets of levers, one of which is relatively short to become effective at the end of the cam operation and the other of which is relatively long collapsible levers which reach an efficient operating angle at the end of the operation of the short levers.

The above and other objects and features of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which:

Figure l is a partial side elevation of a lift truck equipped with an unloading device embodying the inventron;

' Figure 2 is a View similar to Figure 1 showing the parts in full unloading position;

Figure 3 is a perspective view of the unloading mechanism in full unloading position;

"Figure 4 is a partial perspective view of the container orboiq" Figure 5 is a disassembled perspective view of the unloading mechanism;

Figure 6 is a plan view of the unloading mechanism; and

Figures 7, 8, and 9 are perspective views of the unloading mechanism illustrating different positions thereof.

The unloading mechanism of the present invention is adapted to be used with a conventional fork truck having an upright frame 10 carrying a fork unit 11. The fork unit is mounted on supports 12 which may be moved vertically on the frame 10 through a chain 13 or the like to pick up and transport loads.

The fork unit 11 as shown in detail in Figure 3 comprises a pair of uprights 14 which are adapted to be connected to the supports 12 to be elevated thereby. The uprights 14 carry a frame formed by. a pair of inwardly facing channel frame members 15 serving as vertical guide tracks for a carriage 16. The carriage 16 carries rollers 17 riding in the channels 15 to support and guide the carriage for vertical movement on the frame members 15. The carriage may be elevated 'by a hydraulic cylinder 18 whose piston rod 19 is connected directly to the carriage, as shown in Figure 3. I

The carriage pivotally carries a supporting bar 19 whose vertical length is substantially equal to the height of a box or container to be lifted. At its upper end the supporting bar 19 is pivoted to thecarriage 16 on a horizontal axis and is formed with a reduced extension 21 projecting above the pivot to engage the box or container as described hereinafter. At its lower end the supporting bar is preferably wider to provide an enlarged surface for engaging the box and has inwardly turned flanges 22 which are cut off at the upper edge at an angle to provide cam surfaces 23. When the carriage is lowered the flanges 22 overlie the sides of the channel frame members 15 as shown in Figure 7 and the cam surfaces 23 lie directly beneath cam rollers 24 mounted on the channel frame members 15. When the carriage is elevated the cam surfaces will cooperate with the rollers 24 to move the lower end of the supporting bar outward from the frame as shown in Figure 8.

For further tilting movement of the supporting bar outward from the frame, levers 25 are provided, pivoted on the lower end of the supporting bar, and urged to a position projecting outward therefrom as shown in Figure 3 by springs 26. The free ends of lever 25 cooperate with fixed guide plates 27 mounted on the frame members 15 and positioned to engage the ends of the levers and hold them in vertical position when the carriage is lowered as shown in Figure 3. During initial upward movement of the carriage, while the cams 2324 are the ends of the levers will engage stops 28 at the upper ends of the guides 27 to stop sliding movement of the levers. At this time the levers are at such an angle as shown in Figure 8 that they will be effective during further upward movement of the carriage to swing the lower end of the supporting bar further outward from the frame to the position shown in Figure 9.

To swing the supporting bar still further outward an additional lever mechanism is provided consisting of tele scoping levers 31 pivoted at the upper end to the frame members 15 and at their lower ends to the lower'portion of the supporting bar. During upward movement of the carriage through the two steps described above, the telescoping levers 31 will collapse freely and will reach the limit of their collapsability when the parts are in the position shown in Figure 9. Upon continued upward movement of the carriage the levers 31 become elfective to swing the lower end of the supporting bar still further outward from the frame to the extreme position shown Patented July 2, 1957' 3 in Fi guresi2"an'd-.3. .:At thistime the levers 25 will swing away from the guides27v and. willbe held projecting outward from the supporting bar by the springs 26.

When the carriage is lowered the ends of the levers 25: engage theutops-portions: ofsthei guides. 27 andwill be swung inward by the guides 27 tofth'e star-tingposition shownzinzliiguresil and: 7-. \During this movement, the

telescoping lever 31 will extend to the position shownin Figures Land. 7: so -;that'.the-.mechanism automatically: returnsiitselfzto operating. conditions I .i'llhe'imech'anism is adaptedato'be used; with abox or containerzas shownnin: Figures 1, 2,- and 4 -whichmay be of rectangular shape with vertical side and end walls 32.

The .bottomof the box is closed by ahinged closure '33- pivoted at' one end to: the bottom of an end wall--34 of the box on hing-es35. The box bottom-may carry rollers OI f OOt-"m6mbCI'S- 36%0 elevate it above-the floor so that the forks ofthe truck can-be-slippedunder the. box to pickit-upr The end- 34 f the-box on which the -hinges are provided -is'preferablyreinforced by angle-bars 36 extending vertically-along the end ofthebox and spaced apart torec'eive the supportingbar between them. Near the upper end of the box-a pair of spaced lugs37 are provided connected by'apin 38 which-is spacedfrom the end of the box. The lugs 37 and pin 3'8 are-so spaced as to receive the reduced projection 21 of the-supporting bar between the lugs andbetween the pin- 38 and the end of the box thereby to connect the box to the supporting 'bar for elevation and tilting therewith. Preferably the top edge of the end 34' extends inward at an angle as indicated at 39 so that the box can be ofgreater height than the supporting'bar' and'can be picked up and tiltedthereby Without interference with the tilting-mechanism and with the-.ability-to holda full load of material.

'In' using this-device a-box maybe picked up on the forks-with the-carriagelowered as shown in Figure 1 and with-the supporting barlying'between' the angle strips 36. The b'ox maybe elevated by the forks to any desired position at-which the material therein is to be unloaded in the usual manner. To'unload the material the hydraulic cylinder 18- is energized toelevate' the carriage 16. Duringinitial upward movement the projection 21 will slip between the lugs 37 and between the end of the box and the pin 38 to secure the box to the supporting bar. It can be seen that this operation can beperformed without any'directattention on the part of the operator other than-controlling hydraulic cylinder.

As'thecarriage continues to rise the cam surfaces 23 will ride over the rollers 24' to tilt the lower end of the supporting bar and of the box outward. This will tilt the outer'end of the box upward away from the bottom 33 and at'the'same time the bottom will tend to pivot downward about the hinges 35 since it has-been elevated above the forks'll. Material in the box will, therefore, start to spill out promptly over the front edge of the bottom 33 into" any desired location.

As the carriage continues to move upward the supporting-bar will be tilted further outward first by the levers 25 and then by the telescoping levers 31 until the box is in its full unloading position as shown in Figure 2. In this position the end 34 of the box and the bottom 33 form a substantially straight continuous surface at an acute angle at the horizontal so that all material in the box will flow therefrom.

Upon completion of'the unloading operation the parts maybe returned to the position of' Figure 1 ready to receive a new loaded box.

"While one embodiment of the'invention has been shown and describedin detail, it will be understood that this is forlthe purpose of illustrating only and is not to be taken as'a definition of the scope of theinvention, reference being had forthis purpose to the. appended claims.

7 What i's 'cl'aimed is:

1'. A material unloading .-.device forr use onliftrtrucksj and the like comprising a container having its bottom hinged at one end, a supporting frame, a carriage movable. vertically on the frame, a supporting bar pivoted on the carriage on a horizontal axis, interengaging parts on the supporting bar and said one end of the container to connect the container to the supporting bar to be elevated thereby, and means operatively connecting the supporting bar and the frame to swing the lower end of the supporting bar outward. from the frame as the carriage is moved upward on the frame thereby to tilt the container upward.

2. A material unloadingndevice for: use on. lift trucks and the like comprising a container having its bottom hinged at one-end,-a supporting frame, a carriage movable vertically on the frame, a supporting bar pivoted on the carriage on a horizontalaxis; interengaging parts on the supporting bar and said one end of the container to connect the container to the supporting bar to be elevated thereby, and telescoping links connected at their opposite ends .to the frame.- andzthe. lower end. of thesupporting bar to telescope during. initial-upward movementof-the carriage and thereafter .to swing. the lower end of the supporting bar outward from the frame as the carriage continues to. moveupward- SJA-material: unloading device foruse on lift trucks andv the like' comprisinga containerhaving its bottom hinged-at oneend, a supporting frame, a carriagemovable vertically on -the frame, a supporting bar pivoted on the carriage ons'ahorizontal axis, inter-engaging parts on the supporting bar-and said one end of --the container to connect't-he' container to :thesupporting' bar to be elevated thereby, interengaging parts on-the frame and the supporting bar to swing the lower end of the supporting bar a limited distance outward fromthe frame during initial upward movement of the carriage, and links operatively connecting the frame and supporting bar toswing the lowerend of the supporting bar farther outward during continued upward-movement ofthe carriage.

4.. A- material unloading device for use on lifttrucks and the like comprising a container having it bottom hingedat-one-end, a supporting frame, a carriage movable vertically on the frame, asupporting barpivoted on thecarriageon a horizontal axis, interengaging parts on the supporting bar and said one end of the container to connect the container tothe supporting bar to be elevated thereby, interengaging parts on the frame and the supporting bar to swing the lower end of the supporting bar a limited distance outward from the frame during initial upward movement of the carriage, a pivoted arm and a guide members one mounted on the supporting bar and the other on the frame, the guide member slidably engaging the free end of the arm during said initial upward movement and including a stop engageable with the end of the arm to cause it to swing in a direction to force the lower end of the supporting bar farther outward during continued upward movement of the carriage.

. 5. A material unloading device for use on lift trucks and the like comprising a container having its bottom hinged at one end, a supporting frame, a carriage movable vertically on the frame, a supporting bar pivoted on the carriage on a horizontal axis, interengaging parts on the supporting bar and said one end of the container to connect the container to the supporting bar to be elevated thereby, interengaging. parts on the frame and the supporting bar to swing the lower end of the supporting bar a limited distance outward from the frame during initial upward movement of the carriage, and collapsible telescoping links connected at their ends to the supporting bar and the frame to collapse during said initial movement of the carriage and to force the lower end of the supporting bar to swing farther out during continued upward movement of the carriage.

6. Amaterial unloading device for use on lift trucks and the like comprising a container having its bottom hinged at, oneend, a SUPPOrtingframe, a carriage movable vertically on the frame, a supporting bar pivotedon the carriage on a horizontal axis, interengaging parts on the supporting bar and said one end of the container to connect the container to the supporting bar to be elevated thereby, interengaging cam elements on the frame and the supporting bar to swing the lower end of the supporting bar outward from the frame during initial upward movement of the carriage, and links acting between the supporting bar and the frame to swing the lower end of the supporting bar farther outward from the frame during continued upward movement of the carriage.

7. A material unloading device for use on lift trucks and the like comprising a container having its bottom hinged at one end, a supporting frame, a carriage movable vertically on the frame, a supporting bar pivoted on the carriage on a horizontal axis, interengaging parts on the supporting bar and said one end of the container to connect the container to the supporting bar to be elevated thereby, interengaging cam elements on the frame and the supporting bar to swing the lower end of the supporting bar outward from the frame during initial upward movement of the carriage, and collapsible telescoping links connecting the supporting bar to the frame to collapse during said initial movement and to swing the lower end of the supporting bar farther outward during continued upward movement of the carriage.

8. A material unloading device for use on lift trucks and the like comprising a container having its bottom hinged at one end, a supporting frame, a carriage movable vertically on the frame, a supporting bar pivoted on the carriage on a horizontal axis, interengaging parts on the supporting bar and said one end of the container to connect the container to the supporting bar to be elevated thereby, interengaging cam elements on the frame and the supporting bar to swing the lower end of the supporting bar outward from the frame during initial upward movement of the carriage, a pivoted arm and guide member one mounted on the arm and the other on the frame, the guide member slidably engaging the free end of the arm during said initial upward movement and including a stop engageable with the arm to cause it to swing in a direction to force the lower end of the supporting bar farther outward during a second stage of upward movement of the carriage, and collapsible links connected to the supporting bar and the frame to collapse during the initial and second stage movement of the carriage and to force the lower end of the supporting bar to swing 6 still farther out during a third stage of upward movement of the carriage.

9. A material unloading device for use with lift trucks and the like comprising a vertically movable carriage, a supporting bar pivoted adjacent to its upper end on the carriage and including a reduced projection at its upper end, a container having its bottom hinged to the container at one end, a pair of spaced lugs projecting from said one end of the container adjacent to its top to receive the reduced projection between them, and a cross member connecting the lugs to fit over the projection whereby the supporting bar is connected to the container to raise it.

10. In a material unloading device for use with lift trucks and the like, a container having vertical side and end walls, a bottom hinged to one of the end Walls, a pair of spaced parallel bars extending vertically along said one end wall of the container, a pair of spaced lugs projecting from said one end wall adjacent to the tops of the spaced parallel bars, and a cross member connecting the lugs and lying substantially parallel to and spaced from said one of the end walls, the spaced parallel bars being adapted to receive between them a supporting bar for lifting and tilting the container with the upper end of the supporting bar fitting between the lugs and between the cross member and said one end of the container.

11. A material unloading device for use with lift trucks and the like comprising a vertically movable carriage, a supporting bar pivoted adjacent to its upper end on the carriage and including a reduced projection at its upper end, a container having side and end walls and a bottom hinged to one of the end walls, a pair of elongated spaced parallel bars extending vertically along said one end of the container to receive the supporting bar between them, a pair of spaced lugs adjacent to the upper ends of the bars to receive the reduced projection between them, and a cross member connecting the lugs and spaced from the container end wall to overlie the reduced pro jection.

References Cited in the file of this patent UNITED STATES PATENTS 2,186,478 Dehuff Jan. 9, 1940 2,639,829 Dempster et al May 26, 1953 2,678,743 Backofen et al May 18, 1954 

